Movable barrier operators generally serve to selectively move a movable barrier (such as a segmented or one-piece garage door, swinging gate, sliding gate, rolling shutter, and so forth) between an opened and a closed position using one or more motors. It is known to use safe-operation sensors with such operators to aid in ensuring that the movable barrier can be so moved without undue risk to persons or property in the immediate vicinity. Typically, such sensors are designed to detect an obstacle in the path of the moving barrier (particularly when the moving barrier moves to a closed position) through use of light, sound (including ultrasonic sound), radio-frequency, and/or contact sensing mechanisms. In one example, a sensor beam is made to travel across the garage door opening, preferably in a direction generally parallel to the garage floor. Passage of the beam across the garage door opening is continuously monitored.
Upon sensing an obstacle, the sensor provides a corresponding signal, which signal can be used by the movable barrier operator accordingly to aid in avoiding potentially harmful contact between the movable barrier and the detected obstacle. For example, should a sensor detect an obstruction present in the barrier opening, the movable barrier operator may respond by stopping and/or reversing motor energization to stop and/or reverse barrier movement.
Obstacle detection systems often utilize two or more components. For example, a typical obstacle detection system used in a residential garage setting may include a transmitting component placed at one corner of the entryway, and a receiving component placed at the opposite corner of the entryway. Thus, the distance between the two sensor components is approximately the width of the barrier or the barrier opening. A typical residential garage door may range from approximately 9 feet wide to approximately 16 feet wide. In commercial applications, a movable barrier may be approximately 40 feet wide.
In order to function properly, the sensor components must be in alignment. On existing sensor components, a small light-emitting diode (LED) on one or more of the sensor components informs an installer of the alignment status. When the sensor components are not in alignment, the LED will not light up. However, when the installer moves a sensor component into alignment with another sensor component, the LED on one or both of the aligned sensor components lights up. Another method of aligning sensor components of an obstacle detector system includes using a beam of visible light extending from one sensor component to another.
Aligning sensor components of an obstacle detector system can be a tedious, time consuming process. Furthermore, aligning sensor components becomes increasingly difficult as visibility of the LED or beam of light decreases. For example, as the distance between two sensor components increases, it becomes increasingly difficult for the installer to determine whether the LED on the distant component is lit. Additionally, environmental factors such as direct sunlight or airborne particles may obstruct visibility of a distant LED or beam of light.